A local store, the wonderful Uwajimaya, and the Internet have started a slow "tour" of the various different flavors of Kit Kats from Japan. Mostly because they're exciting and could potentially be really good, but also because in the US the Kit Kat brand is owned by Hersheys. Not only do our Kit Kats taste different than similar plain chocolate Kit Kats from other countries, such as the UK, they're also only offered in white, regular, and dark chocolate. Other flavors are basically unheard of, despite knowing the popularity of the Japanese flavors.
Many of these flavors are limited edition, sold only in certain regions of Japan, or otherwise temporary. So this list may grow quite a lot but not have many checked off. Such is the life of someone who isn't prepared to spend all their time and money tracking down flavored sugar. Wonderful pretty sugar.
Below is a list of all flavors I know of, and which ones I've tried. The key is as follows: